/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.search;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Collector;
import org.apache.lucene.search.Scorer;

import java.io.IOException;

/** A simple delegating collector where one can set the delegate after creation */
public class DelegatingCollector extends Collector {
	static int setLastDelegateCount; // for testing purposes only to determine
										// the number of times a delegating
										// collector chain was used

	protected Collector delegate;
	protected Scorer scorer;
	protected IndexReader reader;
	protected int docBase;

	public Collector getDelegate() {
		return delegate;
	}

	public void setDelegate(Collector delegate) {
		this.delegate = delegate;
	}

	/** Sets the last delegate in a chain of DelegatingCollectors */
	public void setLastDelegate(Collector delegate) {
		DelegatingCollector ptr = this;
		for (; ptr.getDelegate() instanceof DelegatingCollector; ptr = (DelegatingCollector) ptr
				.getDelegate())
			;
		ptr.setDelegate(delegate);
		setLastDelegateCount++;
	}

	@Override
	public void setScorer(Scorer scorer) throws IOException {
		this.scorer = scorer;
		delegate.setScorer(scorer);
	}

	@Override
	public void collect(int doc) throws IOException {
		delegate.collect(doc);
	}

	@Override
	public void setNextReader(IndexReader reader, int docBase)
			throws IOException {
		this.reader = reader;
		this.docBase = docBase;
		delegate.setNextReader(reader, docBase);
	}

	@Override
	public boolean acceptsDocsOutOfOrder() {
		return delegate.acceptsDocsOutOfOrder();
	}
}
